The wet deposition of acid and some major ions over the Japanese Archipelago

Abstract

The wet deposition of acid and some major ions over the Japanese Archipelago was presented. The country was divided into 15 climatic regions with 114 grid squares, and the annual and seasonal fluxes of non‐sea salt sulfate, nitrate, ammonium and non‐sea salt calcium were estimated. Wet deposition fluxes were determined from CRIEPI's regional monitoring data at 21 sites between October 1987 and September 1990. The concentration of these ions in precipitation increased during the cold season, and this tendency was noted on the northwestern region facing the continent across the Japan Sea. Estimated wet deposition of [nss‐SO42−]+[NO3−], here defined as the acidic component (AC), was approximately 75 meq m−2 yr−1, and that for [NH4+]+[nss‐Ca2+], here defined as the basic component (BC), was approximately 52 meq m−2 yr−1. If the concentration difference of AC − BC was converted to the wet deposition of H+, it was approximately 23 meq m−2 yr−1, or the total deposition over the Japanese Archipelago was approximately 17 Geq yr−1. For Japan as a whole, wet deposition of inferred H+ in the warm season and the cold season accounted for 45% and 55%, respectively. In the warm season, the major receptor of acid was the climate regions facing the Pacific Ocean, while in the cold season it was the climate regions facing the Japan Sea. The wet deposition over the Japanese Archipelago was influenced by two factors: meteorological conditions such as the wind system and rainfall pattern due to Asian monsoons, and the geographical distribution of emission sources of chemical substances through natural and anthropogenic activities in East Asia. It was suggested that in‐flow of chemical substances from outside the region plays an important role in the wet deposition field over the Japanese Archipelago.

Factors controlling the acid‐neutralizing capacity of Japanese cedar forest watersheds in stands of various ages and topographic characteristics

“…The pH of streamwater was neutral in GEF ( Figure 2) similarly to the values commonly reported in Japan (Nakagawa and Iwatsubo, 2000;Toda et al, 2000;Ikeda and Miyanaga, 2001;Asano and Uchida, 2005). In addition, the concentrations of SO 4 2 , NH 4 C and NO 3 in bulk deposition, which make terrestrial ecosystems acidic (Driscoll et al, 2001), were below the averages in Japan and east Asia (Hara et al 1995;Fujita et al, 2000Fujita et al, , 2003Noguchi et al, 2007), as well as eastern North America and Europe (Lehmann et al, 2005). The study site is located 70 km from the nearest urban area (Osaka city), so the influence of anthropogenic sulphur and nitrogen compounds on precipitation chemistry and resultant acidification of forest ecosystems are considered relatively small.…”

“…acid rain), and (2) internal H C production during decomposition and nitrification processes in soils, dissolution of CO 2 released by biological respiration, and cation uptake by vegetation (van Breemen et al, 1984;van Miegroet and Cole, 1985;Reuss et al, 1987;Gundersen and Rasmussen, 1990). The external inputs have received a lot of research attention because anthropogenic acid deposition and its long-term impacts on ecosystems remain high in North America and Europe (Likens et al, 1996;Stoddard et al, 1999;Driscoll et al, 2001;Holland et al, 2005), and are increasing in eastern Asia (Larssen and Carmichael, 2000;Kuylenstierna et al, 2001;Fujita et al, 2003;Galloway et al, 2004;Larssen et al, 2006).…”

Nitrogen use byPinus densifloratrees growing on a Mt. Fuji lava flow

“…The wet N deposition for the study site was estimated by the mean concentrations of nitrate (NO 3 Ϫ ) and ammonium (NH 4 ϩ ) as reported by Fujita et al (2000) from 1987 to 1990 and by the mean monthly precipitation obtained from the Kawaguchiko Meteorological Station during the same period. Among the data reported by Fujita et al, we specifically employed data on NO 3…”

Wet and dry deposition of sulfur associated with the eruption of Miyakejima volcano, Japan

“…Although estimated deposition velocities vary with meteorological conditions, land use type and so on, values from 0.2 to 1.0 cm s À1 for SO 2 and 0.1 to 0.4 cm s À1 for nss-SO 4 2À fine particles were reported. The annual dry deposition of sulfur in late 1980s throughout Japan was approximately 430 Â 10 9 gS yr À1 (0.60 mgS m À2 yr À1 ), with the contribution of SO 2 accounting for 90% of the total and that for the particulate sulfate as little as 10% of the total [Fujita et al, 2003].…”

“…Although the precipitation amount changed year-to-year, concentration of nss-SO 4 2À in precipitation throughout Japan has remained almost unchanged during the last ten years. Annual wet deposition of sulfur in late 1980s throughout Japan was approximately 620 Â 10 9 gS yr À1 (0.86 mgS m À2 yr À1 ) and the wet deposition was significant on the Japan Sea side during the cold season [Fujita et al, , 2003].…”